Jig fixture



z. HAYDU ET AL JIG FIXTURE June 3, 1958 3 Sheets-Sheet 1 Filed Nov. 28, 1955 I INVENTORJ ZoLm/v HIM? ARrHuR .SurTa/v June 3, 1958 z. HAY-DU ETAL 2,836,879

JIG FIXTURE Filed Nov. 28, 1955 3 Sheets-Sheet 2 IN VEN TORS ZoLT/w HH YDLL BY ART/1w? SMTTOIV ATTORNEY June 3, 1958 z. HAYDU ETAL 2,836,879

JIG FIXTURE Filed Nov. 28, 1955 s Sheets-Sheet 3 IN VEN TORS ZOLTHN Hmwu BY ART/1a Sari/01v TTORNEY yrs-1 56 EXTURE Zoltan Haydn, lainiield, and Arthur E. Sutton, New Market, N. 3., assicnors, by mesne assignments, to Burroughs Corporation, a corporation of Michigan Application November 28, 1955, Serial No. 549,259

16 Claims. (Cl. 2=3-=-25.19}

This invention relates to a jig fixture and in particular to one for precisely positioning, spacing, and assembling small components of a device requiring critical relationships. The invention is particularly useful in jig fixtures for assembling the electrodes of an electron tube and is therefore hereinafter described as embodied in a fixture for this purpose.

An example of an electron tube which the invention is eminently suitable in producing is one described in Electronic Design January 1954, pages 14 and 15, and also described in U. S. Patent No. 2,721,955 issued October 25, 1955. This tube is a beam switching type utilizing the combined efiects of a magnetic field, produced by an external cylindrical magnet, and electric fields, produced by its internal electrodes, to form, switch and modulate an electron beam in a number of discrete automatically locked positions. For ten positions, the internal elements of the tube include an elongated indirectly heated cathode, a circular array of ten U-shaped spade electrodes for forming and locking the beam, a circular array of ten L-shaped target electrodes, and ten rod-type switching grids. Attention is invited to the aforementioned publication and patent for a more complete description of the construction of this tube and its uniquely versatile performance capabilities.

In electron tubes of this type, the large number of internal electrodes are generally assembled and supported between a pair of insulating, e. g. mica, discs and permanently enclosed within a sealed glass envelope. The position and spatial relationships of the electrodes are very critical for proper operation of the tube, and the electrode assembly. must be rugged enough to maintain the critical relationships during handling and use. In producing these electrode assemblies in the past, the

general procedure was to manually insert each electrode individually in its proper position between the supporting mica discs. This was accomplished by inserting the lower tabs of the electrodes individually in their respective punched openings of the lower mica disc, with the tabs biting into, or tightly wedged against, the edges of the opening, and then inserting the upper mica disc through the upper tabs of the electrodes. This procedure was a long and tedious one but was felt to be necessary to assemble all electrodes in their critical position and spacing relationships. Nevertheless, these re lationships could still not be completely and uniformly held to the critical degree required, which resulted in a high percentage of rejects. Moreover, in manually inserting the individual electrodes through the mica disc openings, it was frequently necessary to turn or twist the electrodes in their openings to work them in and to secure the required critical relationships. This would result in deforming the edges of the mica openings which weakened their support of the electrodes during handling and use of the tube, thereby producing erratic operation of the tube after relatively short use.

The use of a jig fixture embodying the invention heretrode assemblies for electron tubes.

inafter described has not only enabled the production of electrode assemblies minimizing the above deficiencies, but has also decreased, to a fraction, the time heretofore required to produce such assemblies. While the invention is eminently useful in the production of electron tubes, it will be quite apparent that it is susceptible of many other applications for assembling small components of a device requiring critical position and spacing relationships.

It is therefore a primary object of this invention to provide a jig fixture which is efiicient and accurate in the positioning, spacing, and assembling of small components of a device requiring critical relationships.

Another object of the invention is to provide a jig fixture utilizing a vacuum for accurately positioning components of a device as they are being assembled.

A further object is to provide a jig fixture for accurately positioning a plurality of small components on a common support and simultaneously anchoring all the components to the support whereby they will be uniformly and firmly secured in their proper positions.

Still further objects of the invention are to provide a jig fixture of the foregoing character which is especially useful in assembling the electrodes of an electron tube between a pair of mica discs; which accurately positions the electrodes in their critical relationships and retains them in position during their assembly between the mica discs; which securely anchors the electrodes to the mica discs thereby producing a rugged assembly having a long operating life; and which permits the assembly of such devices efiiciently and economically on a mass production basis.

These and still further objects of the invention will be apparent from the following description of a jig fixture embodying the invention for use in producing elec- The electron tube illustrated is of the aforementioned beam switching, ten position, type having ten sets of electrodes that must be critically positioned and spaced, and firmly supported between a pair of mica discs.

The fixture described is provided with a circular array of ten electrode supporting members, one for each set of electrodes, which members are radially projectable from their normal positions to positions corresponding to the placement of their respective electrodes. These members are formed at their inner extremities with surfaces of special configurations'to support their electrodes in the proper position on the mica discs between which they are to be assembled. In the disclosed embodiment for use in connection with the aforementioned electron tube, each member is specially formed to support an L-shaped target and a U-shaped spade in their critical relationships to each other, and an important feature of this invention is the use of a vacuum to retain the electrodes in their proper positions during assembly.

The electrodes are supported by these members in two circular arrays over the lower mica disc seated in a holder of the fixture. A plunger, disposed in a cover hinged to the fixture, may be used to support the upper mica disc. is the feature of forcing the tabs of the electrodes through the openings of the mica disc to uniformly bite, or to be firmly wedged against, the edges of the openings with no other deformation of the edges. This firmly anchors the electrodes to the discs in their proper positions and is accomplished by the plunger arrangement in the cover for forcing the electrode tabs simultaneously and uniformly through the mica disc openings.

The invention will be better understood from the following description of a jig fixture embodying the invention which is especially useful in the production of the Another important aspect of the invention' cation and patent referred to above.

and a. target 10. i i The sections 26 are formed of metal blockshaving their side walls converging"towards, but terminating 7 short of, the central 'axis of 'the' fii ture' thus defining .a circular-well 25 in w hich the chuck members 28 extend 1 f fromitheir respective sections. The; chuck members are. 1 provided at th ir inner extremities with surfaces of.

above referred to beam switching tube, it being appreciated'that the invention could be used with equal advantage in other applications. In the drawings: Figl is a top plan view, partly in section to show internal structure, of a jig fixture constructed in accordance with the invention for use in assembling electrodes ofa beam switching tube betweena pair of mica 'discs; Fig. 2 is a partial sectionalview of the fixture of Fig. 3 is an enlarged fragmentary perspective view,

' partly broken away, illustrating one electrode supporting member, its vacuum means for retaining the electrodes, and the upper and lower mica disc holders'of the fixture," V i Fig. 4 is a top plan view of one of the electrode supporting members and the electrodes supported thereby;

Fig. 5 is a perspective view of the electrode assembly produced withthe aid of the jig fixture; and V 7 Fig. 6' is a top diagrammatic view of the electrode assembly ofPig. 5. i

Referring first to Figs Sand 6 illustrating the electrode assembly produced with the aid of the jig fixture disclosed, ,it will be seen that, such assembly includes an upper and lower insulating, 'e. 'g. mica, disc, 2 and 4 respectively, an elongated indirectly heated cathode 6, and-two 'groups of electrodes, ten in each group, ar-

ranged in circular arrays aroundtheicathode. The inner .group often electrodes are L l-shaped spades 8 and func-' I tion to form and lock. the electron beam, while the'outer group of ten electrodes are L-shap'ed' targets 10 which receive the beam and produce a useful output in any one of the ten. locked positions of the beam: These electrodes are positioned in their critical relationships be tween the two mica discs and firmly secured thereto with the aid of the jig fixture hereinafterldescribed.

The electrode assembly of this type of beam switching tube'includes an additional group of ten rod-type switching ,g'ridsl12 arranged in a circulararray between the spades'fd and. the targets'lit. These electrodes, however,

arelnot assembled by the fixture disclosed as they can be conveniently inserted, in -a' subsequent operation,

through openings in themica discs after theforegoing' electrode-assembly has been produced. For. a descrip tionof the complete structure of ,this tube, including its asses /o s 33 secured to its outer extremity by fasteners- 31.

trodes.

provided with a cylindrical passageway, or bore, 29 longitudinally therethrough, and an apertured end cap A shaft 32 for each section is disposed within the bore 29 and extends through the aperture of end cap 30. -Thef inner portion of. shaft 32 is of larger. diameter and is provided at its inner end with a blind opening in which a boss'33 extending from chuck member'28 is seated and retained by stud 34. The outer portion of'shaft .32, extending through end cap 30,- is of smaller diameter and'carries at its outer extremity a collar 36 fastened thereto by threaded stud 38. Collar 36 abutting against the end cap 30, serves as'a forward stop to limit the forward, or inward, movement of shaft 32 and its chuck member 28, and for that purpose it maybe accurately positioned by its threaded stud 38.5

externalcylindrical magnet, and the performance capabilities of thetube, 'refer encemay be had'to the The jig fiXtureincorporating the. invention for movement from the open position shown in'Pig; l to the closed position shown in Fig. 12: Housing contains the elements of theifixture which position the electrodes in their proper spatial relationships during their assembly between the two mica discs, and cover' 7 7 comprises generally a housing 29 and -a cover; 22 hinged thereto.

publi- 22 contains the meansjfor forcing theelect'rodes into the mica discs to firmly secure them in place.

Referring to Fig. 2, the housing'ZO comprises a base" plate 24 which supports the means for positioning the electrodes, these means being disposed in a plurality of sections 26 arranged in a circular array directed towards the central aXis of the fixture. Each of the sections 26 whichfpositions its respective electrodes. In the fixture disclosed for use in connection with the aforementioned tube, there are ten sections 26 each having a chuck member 28 for supporting .two electrode's i, e. a spade 8 To limit the return movement of chuck members 2 8, each of the shafts 32 is provided with a sleeve 40' pressfitted thereon and. a'bushing 42 pinned thereto.

42 serves as a'retui'n stop for chuck'member 28.1

In the fixture disclosed,'-pneurnatic meansare used to project and return the ichuck members 28s For this purpose, bushing 42 and-rend cap areprovided with "sealing rings 44 and 146, respectively,*-for sealing the expansible chamber 143 defined by these elements within the passage 29. Channcls 48. formed inthe endcap -30 communicate at one end with expansible chamber 43 and at thev other endwith an :air hose con'nector49 connectable to an 'air *supply/for all the sections, not

shown. It will thus be seen that as' air is, forced into the e pansible chambers 43, the shafts 32 and their chuck members 28 will be projected inwardly until their collars' 36 limit'on end caps 30 (as shown in Fig. i);

and as the air is exhausted, these members will be .re-,

turned to the position of tact end caps 30. a Thelarger diameter portion of shafts 32*are flattened at 32', and metalinserts 50, securedto sections 26 by fasteners 51, are providedwith depending flanges 52 in Fig. 2 wherein sleeves concontact with the fiattenedsurfaccs 32. This arrangementconstrains shafts 32 from any rotary movement and 7 also vents to the atmosphere the air trapped in passage 29. A- cylindrical plastic sleeve '54 in each" of thepas sages 29 separates shafts 32 from the inner surfaces of.

sections 26. I

' Housinglll is also provided with means for holding" the lower "mica .disc'4' in position during its assembly with electrodes 8' and 10; A cylindrical tube 60, closed at one Iend,'is secured at its open end .to an opening in I the base plate'24, by fasteners 62, along the central .aXis

. of the. fixture and directly below the circular well. 25

houses an electrode supporting, or chuck, .member- 23 p i defined sby sections 26; -Tube 60carries a shaft64, at one end of which is secured a mica holder 66=havinga depending boss 68 retained in a blind opening ofthe shaft by' stud 70.. A plastic sleeve- 71 is interposed between shaft 64 and tube .60, and extends through the" opening in base plate 24 to be flush with its topsurfacei The foregoing structure supports lower mica disc 4.during its assembly, and also supports the-electrode assembly after it is completed in a manner later described; To facilitate-the; removal of :the complete' as V sembly from the fixture, either manually or .autom'at'n: cally,; it is 'desirable'to raisejrmica holder. 66 "out ofthe I i For this purpose, each of .thepsectionsl26 is.

Sleeve abutting againstend cap Chianti retainedby'bushing circular well. For this purpose, a dished disc 72 is secured to the lower end of shaft 64 by a fastener 74, and the closed end of tube 50 is provided with an air channel 76 communicating with the air source (not shown) by connector 78 controlled by air valve 80. Thus, mica holder 66 is projectable out of the circular well by pneumatic means. As air is forced into channel 76, shaft 64 and mica holder 66 are raised until disc 72 contacts sleeve 71, and as the air is exhausted, the elements are returned to the position shown in Fig. 2 with the disc 72 resting against the closed end of tube 60. Shaft 64 is provided with a longitudinal groove 64 in which is seated stud 82 passing through tube 60 and sleeve 71. This prevents any rotary movement of the shaft and also vents the air that may be trapped within tube 60 above disc 72.

The lower mica disc holder 66 is shown in detail in Fig. 3. A thickened rim 90 thereof circumscribes the surface of the holder adapted to contain the mica disc 4, the latter having projections, or tabs, 92 snugly engaging the rim. The holder 66 is further provided with an inner circular trough 94 to accommodate the tabs of the spade electrodes 8 and an outer circular trough 96 to accommodate the tabs of the target electrodes 19. The disc holder 66 is further provided with three projecting pins 98 adapted to pass through corresponding punched apertures in mica disc 4. These pins are so spaced to assure that the disc 4 will be properly positioned in the holder with the upper surface facing up and with its punched openings in registration with the electrode tabs. A counter-bored opening 97 is further formed in the holder 66 in which an elongated pin 99 is disposed. The pin passes through a central punched aperture in the mica disc 4, when the latter is placed thereon, and support the elongated tubular cathode 6;

As shown in Fig. 3, the punched openings 5 in the mica disc 4 receiving the tabs of electrodes 8 and 19 are triangular in form, and have one side thereof 5 of the same dimension as, or preferably slightly smaller than, the width of its corresponding electrode tab. Accordingly, when the electrode tabs are forced through the openings in the mica discs, in the operation later to be described, they will bite into, or be firmly wedged against, the edges bordering the ends of sides 5" of the openings 5, thereby securely anchoring the electrodes to the discs.

As mentioned earlier, housing 26 has associated therewith a cover 22 containing the means for forcing the upper and lower mica discs into secure engagement with the electrodes. Referring to Fig. 2, cover 22 comprises a sleeve 3 having an enlarged annular flange 102 at the lower end thereof pivotally mounted to the housing by means of a hinge 1G4 and bolts 1435 and 1&6. An upper mica disc holder 1% is supported within sleeve 10!) by means of a shaft 110 having a blind opening at its lower end in which a boss 112 of the holder 1&8 is secured by stud 114. Shaft 11% extends through sleeve 19%, separated by plastic liner 115, and is pinned at its upper end to a plunger knob 116 which can be manually depressed to force shaft 11% and its holder 108 downwardly. Thus, it will be apparent that when the electrodes and the mica discs have been properly positioned in the circular well of the fixture, depression of knob 116 will force the electrode tabs simultaneously and uniformly through the mica disc openings. 7

The lower limit of the plunger movement is determined by the lower end of knob 116 abutting against the upper end of sleeve 169, and it will be obvious that knob 116 could be made adjustable on shaft 119 to vary this limit. To limit the upper movement of the plunger, the diameter of sleeve 10!) is reduced, defining a shoulder 117, and shaft 110 carries a bushing 118 to limit thereon. Shaft 110 is also formed with a longitudinal groove 119 adapted to have seated therein a stud 12% passing through sleeve 10!) and liner 115, to prevent rotary movement of the shaft as it is depressed by plunger knob 116.

Referring to Fig. 3, it will be seen that the upper mica disc holder 163 is constructed substantially the same as the lower holder 65, it being formed with a thickened rim 12d, inner and outer circular troughs 124 and 126, respectively, and registration pins 123. A pin corresponding to elongated pin 99 of the lower holder is omitted from the upper holder as the tubular cathode 6 is supported by the lower holder.

Each of the chuck members 23 is formed with surfaces of special configurations to support its pair of electrodes in their proper positions, and each is further provided with vacuum means to retain them so positioned during assembly. These are important features of this fixture, as the two electrodes of each chuck member 2% must be exactly placed in their critical positional and spatial relations with respect to each other and with respect to the electrodes of the other chuck members, and firmly anchored between the mica discs in these critical relationships. Figs. 3 and 4 illustrate the structure of a chuck member 23 for accomplishing this.

The chuck members 28 are each formed with a pair of electrode supporting surfaces for supporting an L- shaped target 10 and a Ll-shaped spade 3 (Figs. 3 and 4). The former supporting surface is formed in sidewall 13B of the chuck member by a notch, or cut-out, defined by walls 131 and 132. Wall 131 is about the. same width as its corresponding side it? of the target electrode, and forms the same angle with wall 132 as does side ll) of the electrode with its other side id". in the embodiment disclosed, the former dimension is 0.144" and the latter angle is Wall 1313, however, extending to the end tip of the chuck member is substantially wider than its corresponding side 10 of the target electrode. in this embodiment, side if?" is 0.ll7 wide, whereas wall'132 to the tip of the chuck member would be about-0.200. Wall 132 merges with curved tip 133, having a short fiattened portion 134, and then joins with the other side wall of the chuck member thus defining the surface for supporting the c -shaped electrode 8. The two straight sides 8' of the U-shaped spade are 0.016 wide, in the embodiment disclosed, and merge with the bi-ght, or looped,

portion 8" having an internal radius of curvature of C2021, forming an angle of about 38 between the twosides. The curved tip 133 of the chuck member, accordingly, also has a radius of curvature of 0.021", and extends for substantially more than half the arc of loop 8''. The flattened portion 134 of the curved tip 133, contiguous to side wall 135, is adapted to engage the portion of the straight side 3' merging with loop 8" of the electrode and thus stabilize the support of the electrode in its proper position. In this position, as is apparent from the drawings, one side 8 of electrode 8 is supported in an overlapping, but spaced, relation to one side 10" of the other electrode 1% 7 To provide the vacuum means for retaining the electrodes in their proper positions on the chuck members, each of the latter is formed with an internal bore 136 connectable to a vacuum source (not shown) through a conduit 137 passing through an elongated opening in the base plate 24. Three spaced air channels 133 are drilled through wall 131 adjacent its inner extremity, and three further spaced air channels 13? are drilled through the curved tip 133, both sets of air channels extending to the internal bore 136. Thus, with the internal bore 136 connected to a vacuum source, the vacuum produced through channels 133 and 139 will retain electrodes 8 and 19 in their proper positions on the chuck members during their assembly with the mica discs.

y A typical operation, described below, illustrates the use of this fixture in assembling the electrodes between the mica discs. At the start of a typical assembly operation, the cover 22 of the fixture would be open as shown in Fig. l, and the chuck members 28 would be in their withsembly from holder 66. The fixture is then drawn positions as shown in Fig. .2. Also, the lower mica disc holder 66 could be-in' its upper position. In, the followingsequence, the operator then performs'the' following steps: inserts a micaldisc 4 in the lower holder.

66 in proper re istration with the pins 98 thereof, and a'tubular cathode over the elongated pin 9 of the holder (see 3.); by the pneumatic controls, lowers holder 66, projects the chuck members 23 into the circular well 25 above the holder, and turns on the vacuum means for the chuck members; manually inserts the ten target electrodes 1%) in the notched portions or" the chuck mem-' bers and the ten spade electrodes 8 against the curved tips of the chuck members; with one hand, inserts a mica disc 2 in the upper holder 1G3 in proper registration with its pins 128 slightly pushing it up within its sleet-e139, 7 andjwith the other hand pivots the cover 223 closed over' the circular well; manually depresses knob lie to its limit thus forcingall the electrodes simultaneously and p uniformly through their respective openings in the mica discs; by the pnehmatic controls, withdraws the chuck members 2.8 and turns 013? the. vacuum source; pivots the cover 22 open and pneumatically'raises lower holder 66 out of the circular well; and removes the'electrode asin condition for the next assembly operation. e I

While the above typical operation taken for illustrative purposes was a simple manual one, it will be apparent that this fixture is susceptible of varying degrees of auto-.

matic operation by the utilization of automatic loading and ejecting devices, and the, provision of automatic controls. Also, the invention could be advantageously embodied in' fixtures for assembling devices other than electrode assemblies. Many other applications and modifications will be apparent to those skilled in the art also coming Within the spirit and scope of the invention as defined in the following claims.

Wc'claim:

1. A jig fixture for positioning and assembling smallv components of a device to .a common support comprising; holder means for the common support, a plurality of members radially projectable over said holder means to positions correspondingto the placement of the compo nents on the common support, said members being adapted to support the components to be assembled in their proper positions, means overlying said members in their pro- .jected positions and adapted to force simultaneously all said components into secure engagement with the common support, and means for radially withdrawing said 1 members from over said holder means to facilitate the 'removal of the assembled components and support.

2. Ajig' fixture for positioning and assembling electrodes between slower and upper insulating disc comprisingj'a holder for thelower insulating disc, a plurality of membersarranged in a circular array for supporting the electrodesto be assembled in their proper positions, means forradially projecting said 7 members over said holder tofthe positions corresponding tothe placement of the electrodes on the lower insulating disc, "acuum means associated with said members for retaining the electrodes in their proper positions, agholder for the upper insulating disc overlying said members in their projected positions, means forfo'rcing' all the electrodes simultaneously into secure engagement with both insulating discs, and means for,radiallywitl'idrawing said members from over saiclholdertolfacilitate the removal ofthe assembled electrodes andinsulating discsi 3. A jig fixture for use in-positioningiand assembling electrodesto an insu t ng disccomprising; a holder for the insulating disc, a mcmberbeing formed with a curved tip at one. end thereof for supporting one electrode and with a notched wall adjacentsaid endtor supporting another. electrode, vacuum means communicating with saidf'curved and notched wallpand means for projecting said member with respect tosaid holder to theposi engagement. with the insulating disc;

8 tion corresponding to the placement of'the electrodes on the insulating-disc.

electrodes to aninsulating disc comprising; a holder for 1 t rung disc, .a member for supportingthe elec-' I trodes, said member being formedwith a curved tip at one :end thereof and with a notchedwall adjacent 'said end, vacuum means communicatingwith said curved tip and-notched'wall, means for projecting said member with respect'to said holder to the positionwcorr esponding to the placement of the. electrodes onthe insulatingdiso'. and plunger means for forcing said electrodes intoisecure 6, A jig fixture for main positioningand assembling" electrodes to an insulating disc comprising; a'holder for the insulating disc, aplurality of members, each for sup? 7 porting a pair of electrodes, arranged in a circular array for raising said holder, for the insulating disc. V 9 A jig fixture for positioning and a'ssembling'eleca trode between a lower and upper. insulating disc com-=1 piising; a housing havinga plurality of sections. arranged,

about saidholder, eachof said members being formed with a curved tip at one endthereof for supporting a first electrode and with ya notched walladjacent said end.

for supporting another electrode in overlapping spaced relation with respect. to the first, vacuum means com? municating with said curved tip and: notched wallof. each member, and means for projecting said members over said holder tolthc positions corresponding to .the placement of the electrodes on the insulating disc.

7. A jig fixture as defined in claim 6 includingplungen; means overlying said members in' their projected lposi-a tions andadapted to forcesimultaneously all the 16153 trodes into secure engagement with the insulating disc. q

8. A jig fixture as defined zin-claun7 including means in a circular array, each of saidrsections having their? side walls converging towards, but terminating short of,

the center axis of the fixture thus defining a circular well,

a holder for the lower insulating disc disposed below: the circular well, a plurality 10f members extending throughlsaid sections into the circular well for'stipport-f irig the electrodes to be assembled in,their.proper po'si-f tions, means for projecting said members over said holder-- to the positions corresponding to the .placementjof the electrodes on the lower insulating'disc, and plunger means 3 including a holder for the upper insulating discoverlying said first-mentionedhdder and said members their projected positions and adapted to force simultaneously 60' all said electrodes into secure engagement with the lower and upper insulating discs,

- 10'. A jig fixture as defined-in claim 9'includinglmeans} at the center of said first-mentioned holder for supporting V a tubular cathode.

11. A jig fixture as defined in claim'9 wherein the sup V porting members are each 'formedw'ith a curved 'tip at; 1

the end projecting into the circular well and, with'a notched wall adjacentsaid end, and wherein each sup? porting memberincludes vacuum means communicating with .said curved tip and notched wall.

12. A jig fixture as defined in claim 11 including means} h for raising'the holder for the lower insulating disc.

13. A jig fixture as defined in' claim712 wherein the? plunger means and the holder for the upperinsulating, disc are disposed in a cover'hinged to s'aid housingi 14. A jig fixture for use in assembling small components of a device between a pair of supports comprising; a holder for each of said supports, a plurality of separate members arranged in a circular array about one of said holders and radially projectable thereover, each of said members being configured to position a plurality of components in mutually spaced relationship and in positions with respect to said holders corresponding to their placement between the pair of supports, means cooperating with one of said holders for simultaneously forcing all the components into secure engagement with the pair of supports, and means for radially withdrawing said members from over said holder to facilitate the removal of the assembled components and supports.

15. A jig fixture for use in assembling electrodes between 21 pair of insulating discs comprising; a holder for each of said insulating discs, a plurality of separate members arranged in a circular array about one of said holders and radially projectable thereover, each of said members being configured to position at least a pair of electrodes in mutually spaced relationship and in positions with respect to said holders corresponding to their placement between the pair of insulating discs, means cooperating with one of said holders for simultaneously forcing all the electrodes positioned by said members into secure engagement with the pair of insulating discs, and means for radially withdrawing said members from over said holder to facilitate the removal of the assembled electrodes and insulating discs.

16. A jig fixture for use in assembling electrodes between a pair of insulating discs comprising; a holder for each of said insulating discs, a plurality of members arranged in a circular array about one of said holders, each of said members being formed with a curved tip at one end thereof for supporting a first electrode and with a notched wall adjacent said end for supporting another electrode in overlapping spaced relation with respect to the first, and means for simultaneously forc ing all the electrodes positioned by said members into secure engagement with the pair of insulating discs.

References Cited in the file of this patent UNITED STATES PATENTS 1,817,746 Gooskens et al Aug. 4, 1931 2,069,086 Donovan et al. Ian. 26, 1937 2,563,468 Hroch Aug. 7, 1951 

